Great Britain has been influenced strongly by its history, and its grand strategy is shaped by both this legacy and by shifting geopolitics. Nevertheless, it has adapted to these forces, adjusted to its post-imperial posture, and remains an influential, nuclear-armed global power. While Great Britain promotes multilateralism and collective security, and is staunch in its alignment to the United States, it is—as Brexit demonstrates—less certain with regard to its relationship with Europe. It is a firm advocate of NATO, but—harking back to the nineteenth nentury—seeks to avoid the dominance of the continent by any single country. This chapter addresses the tension in the GB’s grand strategy through the legacy of its history, its close alliance with the United States, and the influence of domestic politics on key strategic choices. It also addresses the proactive British approach to the Global War on Terror, and the constraints that now impose themselves in the early decades of the twenty-first century.